Return class.

X-Received	by 10.182.213.105 with SMTP id nr9mr11917736obc.36.1406399372840; Sat, 26 Jul 2014 11:29:32 -0700 (PDT)
X-Received	by 10.50.66.179 with SMTP id g19mr300418igt.3.1406399372650; Sat, 26 Jul 2014 11:29:32 -0700 (PDT)
Path	csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!h18no8145946igc.0!news-out.google.com!eg1ni5igc.0!nntp.google.com!h18no4796125igc.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
Newsgroups	comp.lang.python
Date	Sat, 26 Jul 2014 11:29:32 -0700 (PDT)
Complaints-To	groups-abuse@google.com
Injection-Info	glegroupsg2000goo.googlegroups.com; posting-host=101.63.66.74; posting-account=mz2-UgoAAABhHsO0mzb5w7wo3Dt0FOo5
NNTP-Posting-Host	101.63.66.74
User-Agent	G2/1.0
MIME-Version	1.0
Message-ID	<23517efd-6d71-4182-9f18-7aaae3b95afb@googlegroups.com> (permalink)
Subject	Return class.
From	Satish ML <satishmlwizpro@gmail.com>
Injection-Date	Sat, 26 Jul 2014 18:29:32 +0000
Content-Type	text/plain; charset=ISO-8859-1
Xref	csiph.com comp.lang.python:75251

Show key headers only | View raw

Hi,

What does "return Wrapper" do in the following piece of code? Which method does it invoke?
I mean "return Wrapper" invokes __init__ method?

def Tracer(aClass):
    class Wrapper:
        def __init__(self, *args, **kargs):
            self.fetches = 0
            self.wrapped = aClass(*args, **kargs)
        def __getattr__(self, attrname):
            print('Trace: ' + attrname)
            self.fetches += 1
            print(self.fetches)
            return getattr(self.wrapped, attrname)
    return Wrapper


Actual program:

def Tracer(aClass):
    class Wrapper:
        def __init__(self, *args, **kargs):
            self.fetches = 0
            self.wrapped = aClass(*args, **kargs)
        def __getattr__(self, attrname):
            print('Trace: ' + attrname)
            self.fetches += 1
            print(self.fetches)
            return getattr(self.wrapped, attrname)
    return Wrapper
@Tracer
class Spam:
    def __init__(self, *args):
        print(*args)
    def display(self):
        print('Spam!' * 8)

@Tracer
class Person:
    def __init__(self, name, hours, rate):
        self.name = name
        self.hours = hours
        self.rate = rate
    def pay(self):
        return self.hours * self.rate

food = Spam("CARST")
food.display()
print([food.fetches])

bob = Person('Bob', 40, 50)
print(bob.name)
print(bob.pay())

print('')
sue = Person('Sue', rate=100, hours=60)
print(sue.name)
print(sue.pay())

print(bob.name)
print(bob.pay())
print([bob.fetches, sue.fetches])

Back to comp.lang.python | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 11:29 -0700
  Re: Return class. Chris Angelico <rosuav@gmail.com> - 2014-07-27 04:40 +1000
    Re: Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 12:02 -0700
    Re: Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 12:03 -0700
    Re: Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 12:04 -0700
      Re: Return class. Chris Angelico <rosuav@gmail.com> - 2014-07-27 05:16 +1000
    Re: Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 12:21 -0700
  Re: Return class. Satish ML <satishmlwizpro@gmail.com> - 2014-07-26 12:15 -0700

csiph-web